class_docstr: Allow chatbots to be trained with the data from the Ubuntu Dialog Corpus.
docstr: Check if the data file is already downloaded.
docstr_tok: ["Check","if","the","data","file","is","already","downloaded","."]
code: def is_downloaded(self, file_path):
      """
      Check if the data file is already downloaded.
      """
      if os.path.exists(file_path):
          self.chatbot.logger.info("File is already downloaded")
          return True
  
      return False
  
imports: import os
  import sys
  import csv
  import time
  from dateutil import parser
  from chatterbot.conversation import Statement
  from chatterbot.tagging import PosLemmaTagger
  from chatterbot import utils
label_desc: Use image node_id 2 for calling the UbuntuCorpusTrainer obj's underlying member method code with example usage: obj.is_downloaded(file_path) and returns: False, True